Field of the Invention
An embodiment relates to a sheet feeder, an image forming apparatus, and an image forming system.
Description of the Related Art
An image forming apparatus, such as a printer, includes a sheet feeder that feeds and conveys a sheet contained in a sheet containing unit to a conveyance roller disposed downstream of the sheet containing unit. In the sheet feeder, a plurality of sheets fed by a pickup roller is separated into a preceding sheet and a succeeding sheet by a feed roller and a separation roller. When the preceding sheet reaches the conveyance roller, the sheet feeder stops the pickup roller and the feed roller and allows the conveyance roller to draw the preceding sheet (refer to Japanese Patent Laid-Open No. 10-167494). This prevents the succeeding sheet from being conveyed downward of a separation nip in a sheet conveyance path.
While the preceding sheet is drawn by the conveyance roller, a backward tension is applied to the preceding sheet. The backward tension is caused by torque (separation resistance) produced by a torque limiter attached to the separation roller. The backward tension is released immediately when a trailing edge of the sheet comes out of the separation nip. Consequently, the sheet may vibrate to cause a sudden noise. Recently, there have been growing expectations for noise reduction in sheet feeders and image forming apparatuses. Demand for reduced sudden noise levels is increasing in the market.